package cn.pconline.autoclub.util; 


import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

/**
 * 将一个字符串按照zip方式压缩和解压缩  
 * @author zhongwm <zhongweimin@pconline.com.cn>
 * 
 */
public class ZipUtil {
	
    public static String compress(String str) throws IOException {  
        if (str == null || str.length() == 0) {  
            return str;  
        }  
        ByteArrayOutputStream out = new ByteArrayOutputStream();  
        GZIPOutputStream gzip = new GZIPOutputStream(out);  
        gzip.write(str.getBytes());  
        gzip.close();  
        return out.toString("ISO-8859-1");  
    }  
  
    /**
     *  解压缩  
     * @param str
     * @return
     * @throws IOException
     */
    public static String uncompress(String str) throws IOException {  
        if (str == null || str.length() == 0) {  
            return str;  
        }  
        ByteArrayOutputStream out = new ByteArrayOutputStream();  
        ByteArrayInputStream in = new ByteArrayInputStream(  
                str.getBytes("ISO-8859-1"));  
        GZIPInputStream gunzip = new GZIPInputStream(in);  
        byte[] buffer = new byte[256];  
        int n;  
        while ((n = gunzip.read(buffer)) >= 0) {  
            out.write(buffer, 0, n);  
        }  
        // toString()使用平台默认编码，也可以显式的指定如toString("GBK")  
        return out.toString("GBK");  
    }  
	
}
